Five of six Air Force F-35 fighter jets were unable to take off during a recent exercise due to software bugs that continue to hamstring the world’s most sophisticated—and most expensive—warplane.

During a mock deployment at Mountain Home Air Force Base in Idaho, just one of the $100 million Lockheed Martin F-35s was able to boot its software successfully and get itself airborne during an exercise designed to test the readiness of the F-35, FlightGlobal reports. Nonetheless, the Air Force plans to declare its F-35s combat-ready later this year.

Details surrounding the failed exercise were disclosed earlier this week in written testimony presented to Congress by J. Michael Gilmore, the Pentagon’s chief weapons tester.

Gilmore also reported that another test went awry when the software failures forced two F-35s to abort their mission. Rather than improving, the software problems have gotten worse — at least for the Air Force’s F-35 platform. The Marine Corps platform has its issues, too:

Perhaps more troublesome for the F-35 program, overall, is the fact that software stability seems to be getting worse. U.S. Marine Corps F-35Bs loaded with an earlier version of the software are reportedly the most stable, enjoying up to eight hours between “software stability events,” military lingo for glitches in one of the aircraft’s computer programs. The Marine Corps has already declared its F-35s combat ready, though Gilmore acknowledged that in real-world combat the F-35B would require assistance acquiring targets and avoiding threats.

If they have trouble acquiring targets and avoiding threats, then the definition of “combat ready” seems to have fallen victim to a strange type of grade inflation. What kind of combat doesn’t involve target acquisition and/or avoiding threats? Apparently, the Marine Corps is just happy that their F-35s can get off the ground.

Clearly, $100 million doesn’t buy much for the Pentagon these days. Don’t forget that while the comparison these days is to the soon-to-be-decommissioned A-10s, the F-35 was the replacement for the F-22 — a lower-cost alternative as opposed to the $150M price tag on the F-22. The last F-22 rolled off the Lockheed/Boeing line five years ago, but had capabilities that “cannot be matched by any known or projected fighter aircraft.” The decision to halt F-22 production was made seven years ago, when the Pentagon expected the F-35 to arrive in 2010 and reach operational levels by 2012.

How’s that working out for us? We’re four years down the road from that promised target, and the F-35 still can’t acquire that one either. The Pentagon better not put the A-10s in mothballs any time soon.

Update: I apologize for forgetting to put the link into the post. I have fixed it now.